Sub-resolution assist features in semiconductor pattern writing

Abstract

A method for optical proximity correction includes inputting a physical design having a plurality of shapes. Each shape has a plurality of corners, and the physical design is to be exposed on a surface of a substrate. A set of sub-resolution assist features (SRAFs) for the physical design is determined, where a plurality of SRAFs in the set of SRAFs interact. The plurality of SRAFs together provide better dimensional control of one corner of one shape in the plurality of shapes, when exposed on the substrate, compared to using a single SRAF to control a dimension of the one corner. The plurality of SRAFs includes a positive SRAF and a negative SRAF. A modified physical design is output, where the modified physical design comprises the physical design, as modified by the set of SRAFs.

What is claimed is: 
     
       1. A method for optical proximity correction (OPC), the method comprising:
 inputting a physical design comprising a plurality of shapes, wherein each shape comprises a plurality of corners, and wherein the physical design is to be exposed on a surface of a substrate; 
 determining a set of sub-resolution assist features (SRAFs) for the physical design, wherein a plurality of SRAFs in the set of SRAFs interact with each other, wherein the plurality of SRAFs together provide better dimensional control of one corner of one shape in the plurality of shapes, when exposed on the substrate, compared to using a single SRAF to control a dimension of the one corner, wherein the plurality of SRAFs comprises a positive SRAF and a negative SRAF, and wherein the determining is performed using a computing hardware device; and 
 outputting a modified physical design, wherein the modified physical design comprises the physical design, as modified by the set of SRAFs, and the modified physical design is provided for manufacturing semiconductor devices. 
 
     
     
       2. The method of  claim 1  wherein the plurality of SRAFs comprises rectangular SRAFs. 
     
     
       3. The method of  claim 1  wherein the one shape in the plurality of shapes comprises a perimeter, and wherein the negative SRAF is located entirely within the perimeter of the one shape. 
     
     
       4. The method of  claim 3  wherein the negative SRAF is located closer to the one corner than to other corners in the plurality of corners of the one shape. 
     
     
       5. The method of  claim 1  wherein the modified physical design is to be exposed using a laser writer. 
     
     
       6. A method for forming a reticle pattern on a resist-coated reticle, the method comprising:
 inputting a physical design comprising a plurality of shapes, wherein each shape comprises a plurality of corners, and wherein the physical design is to be exposed on a surface of a substrate; 
 determining a set of sub-resolution assist features (SRAFs) for the physical design, wherein a plurality of SRAFs in the set of SRAFs interact with each other, wherein the plurality of SRAFs together provide better dimensional control of one corner of one shape in the plurality of shapes, when exposed on the substrate, compared to using a single SRAF to control a dimension of the one corner, wherein the plurality of SRAFs comprises a positive SRAF and a negative SRAF, and wherein the determining is performed using a computing hardware device; 
 outputting a modified physical design comprising the input physical design modified by the set of SRAFs; and 
 forming a reticle pattern on a resist-coated reticle with the modified physical design. 
 
     
     
       7. The method of  claim 6  wherein the reticle pattern is formed on the resist-coated reticle using a laser writer. 
     
     
       8. The method of  claim 6  wherein the negative SRAF is located closer to the one corner than to other corners in the plurality of corners of the one shape. 
     
     
       9. The method of  claim 6  wherein the one shape in the plurality of shapes comprises a perimeter, and wherein the negative SRAF is located entirely within the perimeter of the one shape. 
     
     
       10. A system for optical proximity correction comprising:
 a device configured to add a set of sub-resolution assist features (SRAFs) to a physical design, the physical design being provided for manufacturing semiconductor devices, wherein: 
 the physical design is to be exposed on a surface of a substrate; 
 the physical design comprises a plurality of shapes; 
 each shape comprises a plurality of corners; and 
 the device is configured to determine a plurality of SRAFs to improve dimensional control on one corner of one shape in the plurality of shapes, compared to using a single SRAF to provide the dimensional control of the one corner, and wherein the plurality of SRAFs comprise a positive SRAF and a negative SRAF. 
 
     
     
       11. The system of  claim 10  wherein the physical design, including the determined plurality of SRAFs, is to be exposed using a laser writer. 
     
     
       12. The system of  claim 10  wherein the negative SRAF is located closer to the one corner than to other corners in the plurality of corners of the one shape. 
     
     
       13. The system of  claim 10  wherein the one shape in the plurality of shapes comprises a perimeter, and wherein the negative SRAF is located entirely within the perimeter of the one shape.